1. Field of the Invention
The present invention relates to a granular agent for ruminants and containing a physiologically active substance which agent is used as a feed or feed additive for ruminants, and process for producing the same. More particularly, the present invention relates to a so-called rumen-bypass granular agent, i.e., an agent in which the physiologically active substance is protected and which is not solubilized in the rumen and is dissolved and absorbed in the abomasum and downstream thereof, and process for producing the same.
2. Description of the Prior Arts
It is known that when physiologically active substances such as amino acids and proteins are orally fed to ruminants, the substances are decomposed by microorganisms and enzymes in the rumens to lose their physiological activities inherent thereto.
Therefore, various granular agents for use in feeds or feed additives for ruminants have been proposed which agents are coated with protective substances that protect them from rumen juice and are dissolved and absorbed in a digestive organ including an abomasum and downstream thereof.
For example, Japanese Patent Publication No. 45224/1974 discloses a production method of an amino acid-containing oil capsule in which an amino acid or polypeptide is dispersed in a molten mixture of a fat and fatty oil having a melting point of 40.degree. C. or higher and another fat and fatty oil having a melting point of lower than 40.degree. C., and the resulting dispersion is poured into water kept at a temperature of between 20.degree. C. and 40.degree. C.
Japanese Patent Publication No. 1057/1981 discloses a granular agent containing a biologically useful substance coated with a matrix comprised by a saturated linear or branched, substituted or unsubstituted aliphatic monocarboxylic acid having at least 14 carbon atoms or salts thereof, or a mixture of such with an unsaturated linear or branched, substituted or unsubstituted aliphatic monocarboxylic acid having at least 14 carbon atoms or salts thereof.
U.S. Pat. No. 4,533,557 (Japanese Patent Application Laid-Open No. 175449/1983) discloses a additive composition for ruminant feeds which comprises a physiologically active substance dispersed in a protective matrix containing chitosan and one or more substances selected from the group consisting of a linear or branched, saturated or unsaturated monocarboxylic acid having 14 to 22 carbon atoms, a hardened vegetable oil and a hardened animal oil in which the protective substance is contained in an amount of 50 to 500 parts by weight per 100 parts by weight of the physiologically active substance, and the amount of chitosan in the protective substance is 0.1 to 90% by weight based on total protective substance.
British Patent Application No. 8501483 (British Patent Application No. 2153199A, Japanese Patent Application Laid-Open No. 168350/1985) discloses granular materials containing a substance useful for a living organism and 20% by weight or more of a water-insoluble salt of a physiologically acceptable acid which has an acidity weaker than hydrochloric acid (such as tertiary calcium phosphate, secondary calcium phosphate, tertiary magnesium phosphate, zinc phosphate, aluminum phosphate, calcium silicate, calcium pyrophosphate, magnesium carbonate, lead carbonate, cobalt carbonate, etc.), and 10% by weight or more of at least one substance selected from the group consisting of a linear or branched, saturated or unsaturated monocarboxylic acid having 14 carbon atoms or more or salts thereof, an animal or vegetable fat and fatty oil having a melting point of 40.degree. C. or higher, and wax having a melting point of 40.degree. C. or higher.
Japanese Patent Application Laid-Open No. 198946/1984 discloses a feed additive containing granules of a physiologically active substance coated with a film which is difficult to dissolve in a neutral or alkaline water but is readily soluble in an acidic water, in which the film is (1) an organic film formed from a film-forming component composed of linear or branched, substituted or unsubstituted, saturated or unsaturated aliphatic monocarboxylic acids having 14 to 22 carbon atoms containing one or more substances selected from one or more of aminocelluloses, polyvinyl-.alpha.-aminoacetates and polyvinylamines, or one or more substances selected from the group of aminocelluloses, polyvinylaminoacetates, polyvinylamines and chitosan, and one or more substances selected from the group consisting of hardened vegetable fats and fatty oils, and hardened animal fats and fatty oils, and (2) a film made of one or more inorganic substances selected from metal hydroxides and alkaline metal salts, and a binder, which film is further impregnated or coated with one or more substances selected from the group consisting of aminocelluloses, aminoacetates, vinylamines, aliphatic monocarboxylic acids having 14 to 22 carbon atoms, hardened vegetable fats and fatty oils, hardened animal fats and fatty oils, waxes, beeswaxes, ester gums and water-insoluble binders.
Japanese Patent Application Laid-Open No. 37054/1986 discloses particles of a feed additive containing (A) a physiologically active substance, (B) a substance which is stable under a neutral condition but is disintegrated or dissolved under a weakly acidic condition, and (C) at least one substance selected from linear or branched, saturated or unsaturated monocarboxylic acids having 14 carbon atoms or more or salts thereof, animal and vegetable fats and fatty oils having a melting point of 40.degree. C. or higher, and waxes having a melting point of 40.degree. C. or higher, in which 20% or less of particle size from the surface of each granule is occupied by a coating film made of 10% by weight or more of (B) and 90% by weight or less of (C).
However, the aforementioned prior arts have problems that the granular agents each have insufficient strengths and insufficient solubilities.
That is, in Japanese Patent Publications Nos. 45224/1974 and 1057/1981, while the disintegration of the film substances was expected to take place in a small intestine or downstream thereof, digestion and absorption of the objective substance tended to occur insufficiently.
Also, in U.S. Pat. No. 4,533,557 (Japanese Patent Application Laid-Open No. 175449/1983) and British Patent Application No. 2153199A (Japanese Patent Application Laid-Open No. 168350/1985), use was made of a substance which is capable of being disintegrated to release a physiologically active substance in an abomasum in order to overcome the aforementioned disadvantages, but the disintegration of such substance is insufficient. On the other hand, increase in the solubility results in the loss of durability in the rumen, and therefore no granular composition has been obtained that has both sufficient durability and sufficient solubility. In addition, among the physiologically active substances, it is impossible to increase the content of those substances which have high solubilities under neutral conditions.
In Japanese Patent Applications Laid-Open Nos. 198946/1984 and 37054/1986, the granules are coated in order to increase the content of the physiologically active substances and improve the durability in the rumen, and in order to increase the solubility (releasability) in the abomasum and downstream thereof, use is made in the coating layer of a solubility controlling substance which is sparingly soluble in a neutral or alkaline water but is readily soluble in an acidic water. In the granular agents disclosed in the aforementioned publications, while the increase in the durability in a rumen depends on the insolubility in water of fats and fatty oils used in the coating, the presence of the solubility controlling substance in the coating layer results in insufficient coating, and provides insufficient means for reducing the occurrence of cracks or the like in the coating layer due to the crystallinity of the fats and fatty oils themselves. For this reason, the increase in the durability of the granular agent in a rumen requires the increase in the coating amount, which makes poor the solubility of the granular agent in an abomasum and downstream thereof.
Therefore, it is an object of the present invention to provide a rumen bypass granular agent which can give a physiologically active substance to ruminants efficiently, that is, a granular agent for ruminants which is not solubilized in the rumen but is dissolved, digested and absorbed in the abomasum and downstream thereof. It is also an object of the present invention to provide a process for producing said granular agent for ruminants.